The purpose of this work is to study the mechanisms of control of corneal transparency by means of the use of transport and permeability methods. Animal corneas are used, in vivo or in vitro in anesthethized animals and the fluxes of ions measured across them. The program also involves a study on the retina pigment epithelium of normal frogs, normal rats, and models of retinitis pigmentosa. BIBLIOGRAPHIC REFERENCES: Rufus O. Howard, Jose A. Zadunaisky and Brendan J. Dunn. Localization of Acetylcholinesterase in the Rabbit Cornea by light and Electron Microscopy. Invest. Ophthal. 1975, 14: 592-603. Snyder, W.Z. and Sadunaisky, J.A. A role for Calcium in the Migration of Retinal Screening Pigment in the Frog. Experimental Eye Res. 1976, 22: 377-388.